Dental tool and guidance devices

ABSTRACT

The present invention is directed to a system of devices and a method for preparing a tooth to receive a restoration. The system includes a dental instrument for removal of portions of a tooth in the mouth of a patent and an overlay for guiding the dental instrument during the step of tooth removal. The overlay is designed for temporary installation into the mouth of the patient to guide the dental instrument to remove tooth material. The overlay has one or more sets of guide walls, with a predetermined configuration capable of contacting one or more guide projections of the dental instrument, and a receptacle capable of receiving and attaching to the dental instrument.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/US2012/039569 filed May 25, 2012, which claims the benefit of the filing date of U.S. Provisional Application No. 61/490,361, filed May 26, 2011, entitled Dental Tool and Guidance Devices, the disclosure of all of which are hereby incorporated herein by reference.

FIELD OF THE TECHNOLOGY

The present invention relates to devices and methods for preparing teeth for tooth restorations, and in particular it relates to systems, devices and methods for teeth to receive previously produced tooth restorations.

BACKGROUND OF THE INVENTION

Complete, intact teeth that are cosmetically desirable, that wear evenly and provide a balanced bite are the objectives of patients. Over time, however, problems arise in teeth due to accidents, deterioration from wear and tear, decay, tooth movement, etc. As a result, teeth may become accidentally chipped or cracked from a variety of causes including normal wear and tear, and weakened from decay due to the mouth hygiene and care practices and/or by consumption of certain foods such as sweets, use of tobacco, disease, medications, certain congenital conditions, and environmental effects. To this end, dental practitioners and their patients have relied on a variety of methods to repair these deformities and weaknesses of the teeth.

The repair of teeth often requires preparation and modification of the exterior shape and size of a tooth to be able to receive various prostheses or restorations such as crowns, inlays, onlays, bridges, and veneers. Also, to prepare the appropriate prosthesis or restoration, either impressions or 3-dimensional scanning must be conducted of the original unmodified tooth and the modified tooth. Dental practitioners often place a temporary prosthesis over the modified or prepared tooth while a permanent prosthesis is manufactured, but the use of such a temporary device and the removal of any cement used to place the temporary device over the prepared tooth may create a discrepancy between the prepared tooth and the internal configuration of the prosthesis.

A need has existed in the art to develop a system for more efficiently and reliably treating the teeth of patients for receiving restorations and other prosthesis.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, a system, methods and products have been discovered which provide a simpler, more reliable and more convenient technique for treating a tooth in need of a restoration part, in view of decay, cracks or other maladies existing in the tooth. There is provided a system of dental devices that may be used to modify a tooth by limiting the removal of tooth material to produce a shape or configuration that mates with or corresponds to the interior configuration of a restoration part. This system makes it possible to prepare a restoration part in advance of the preparation of the tooth. Also, the tooth can be accurately prepared with the configuration that corresponds to and mates with the internal configuration of the restoration part. By following this technique, the restoration part is available to be installed immediately after the preparation of the tooth. Therefore, in a single office visit, it is possible for the dentist to prepare the tooth and mount the restoration part onto the prepared tooth.

Under both of these conventional methods and the present invention, there is first a diagnosis indicating the need to treat a tooth with a restoration part. Normally, this is based on initial x-rays or other diagnostic techniques that identify the location and extent of decay, cracks or other maladies of the tooth. A mold, cast, impression, or three-dimensional data must be created based on the original tooth to be treated. At this point the present invention departs from conventional techniques in practice. Conventional techniques require the tooth to be revised and reshaped to remove decay, cracks and other maladies to leave a prepared tooth for receiving a restoration part. After tooth material has been removed, the revised configuration of the prepared tooth must be defined from a second mold or cast or three-dimensional data. The prepared, revised tooth is normally fitted with a temporary crown, to protect the prepared tooth and provide some comfort for the patient until the restoration part is manufactured, which can take days to weeks. Both sets of casts/molds or data are used, usually at an off-site laboratory, to prepare the restoration. The original tooth configuration is the basis for preparing the exterior of the restoration part while the prepared, revised tooth configuration is the reverse or negative for the configuration of the interior of the restoration part.

The procedure of the present invention reduces inconveniences to patients such as eliminating some office visits, and eliminating the need for wearing a temporary crown. Therefore, under the present invention there is no need to prepare the tooth prior to producing the restoration part. There is also no need to produce a cast, mold or three-dimensional data for the prepared tooth prior to installing the restoration part. There is no need for a temporary crown to be installed over the prepared tooth, nor the removal of the temporary crown and associated cement which can create complications with the fit of the restoration part. Such complications can require further revision of the tooth to fit the restoration or further modification of the restoration part. Also eliminated is the discomfort to the patient in wearing a temporary device and the greater risk of infection while the prepared tooth is exposed or is under the temporary crown.

In accordance with the present invention, a system of devices has been discovered for use in the treatment of a tooth to remove certain predetermined portions of the structure of the tooth. The system comprises:

(i) a dental instrument for removal of portions of a tooth in the mouth of a patient, said dental instrument adapted to be utilized with an overlay that is installed over or near the tooth to be treated; and

(ii) an overlay for temporary installation into the mouth of a patient to guide a dental instrument in the removal of tooth structure of the treated tooth, said overlay including a cutting guide utilized with an appropriate dental instrument to limit the movement of the dental instrument during operation to restrict tooth structure removal to the predetermined portion of the tooth, said cutting guide comprising one or more of the following: (a) one or more sets of guide walls, wherein the adjacent guide walls in each set and their surfaces have a predetermined configuration capable of contacting one or more guide projections of a dental instrument to limit the movement of the dental instrument and restrict tooth structure removal to the predetermined portion of the tooth; and (b) a receptacle hingedly or slidedly connected to the overlay and capable of receiving and attaching to the dental instrument, wherein the dental instrument when attached to the receptacle, has limited movement with respect to the tooth to be treated and which restricts tooth structure removal to the predetermined portion of the treated tooth.

With respect to the dental instrument, it comprises: a tooth treatment assembly for removing a portion of tooth structure; and one or more guide projections extending from the instrument in the direction of the working tooth to be treated when the instrument is in position for tooth structure removal, said one or more guide projections being capable of contacting a cutting guide in an overlay device installed in the vicinity of the tooth to be treated to limit the three-dimensional movement of the tooth treatment instrument with respect to the working tooth.

The dental overlay can include the cutting guide as described above or can include other embodiments of the cutting guide in which a receptacle is used for attaching the dental instrument to the overlay where the receptacle is hingedly or slidedly attached to the overlay. When the dental instrument is attached to such a receptacle of the overlay, because the movement of the receptacle is specially limited, the movement of the dental instrument is also limited which restricts its ability to remove tooth structure from the treated tooth to the predetermined portion of the treated tooth.

In another embodiment of the invention a method is provided for treating a working tooth in a patient's mouth by removing portions of its structure, said method comprising the steps of:

determining the three-dimensional structure of the working tooth to be removed for treatment;

providing the dental instrument comprising a tooth cutting element for removal of a portion of a tooth's structure and one or more guide projections extending from the instrument in the direction of the tooth to be treated when said tooth treatment element is in operating position for tooth structure removal;

preparing a dental overlay having a cutting guide with a configuration that is capable of contacting one or more guide projections of the dental instrument to limit the movement of the dental instrument to restrict the structure removed from the tooth under treatment to the predetermined three-dimensional portions of tooth structure for the treatment.

These and other embodiments and further details of the invention are elsewhere described in the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with respect to non-limiting drawings illustrating some preferred embodiments of the invention. In the drawings:

FIG. 1 is a perspective view showing a dental instrument placed in an overlay for use by a dentist in removing tooth structure in accordance with the present invention.

FIG. 2 is a perspective view showing a hand grip and a tooth treatment assembly of the dental instrument of FIG. 1.

FIGS. 3A and 3B are perspective views of two configurations the tooth treatment assembly and a projection head of the dental instrument shown in FIG. 1.

FIGS. 4A and 4B are plan views of two configurations of the projection head and the tooth treatment assembly shown in FIGS. 2 and 3.

FIG. 5 is a perspective view of a dental overlay placed on a patient's teeth for use by a dentist in removing tooth structure in accordance with the present invention.

FIG. 6 is a plan view of the dental overlay shown in FIG. 5.

FIG. 7 is a bottom view of the dental overlay shown in FIG. 5.

FIG. 8 is a perspective view of an alternative arrangement of an overlay placed on a patient's teeth for use by a dentist in removing tooth structure in accordance with the present invention.

FIG. 9 is a perspective view of a further alternative arrangement of an overlay placed on a patient's teeth for use by a dentist in removing tooth structure in accordance with the present invention.

FIG. 10 is a perspective view of a still further alternative arrangement of an overlay placed on a patient's teeth for use by a dentist in removing tooth structure in accordance with the present invention.

FIG. 11 is a perspective view of an overlay device for use by a dentist in removing tooth structure in accordance with the present invention.

FIG. 12 is a plan view of the overlay device shown in FIG. 11 placed on a patient's teeth for use by a dentist in removing tooth structure.

FIG. 13 is a bottom view of the overlay device shown in FIG. 11.

FIG. 14 is a perspective view of an overlay device placed on a patient's teeth for use by a dentist in removing tooth structure in accordance with the present invention.

FIG. 15 is a perspective view of a tooth prior to any preparation of the tooth.

FIG. 16 is a perspective view of the tooth shown in FIG. 15 after preparation of the tooth using the dental instrument of FIG. 1 in combination with the dental overlay of FIG. 5 in accordance with the present invention.

Within the drawings, the same or similar reference numeral is used to correspond to the same or an analogous element.

DETAILED DESCRIPTION

In the Brief Summary of the Invention above and in the Detailed Description of the invention herein, and the claims below, and in the accompanying drawings, reference is made to particular features (e.g., method steps) of the invention. It is understood that the invention embraces and includes all possible combinations of the features described in the text, in addition to those depicted in the drawings. For example, where a particular feature is disclosed in the context of a particular aspect, arrangement, or embodiment of the invention, or a particular claim, that feature can also be used, to the extent possible, in combination with and/or in the context of other particular aspects, arrangements, and embodiments of the invention, and in the invention generally.

The term “comprises” and grammatical equivalents thereof are used herein to mean that other components, ingredients, steps, etc. are optionally present. For example, an article “comprising” (or “which comprises”) components A, B, and C can consist of (i.e., contain only) components A, B, and C, or can consist not only of components A, B, and C but also one or more other components.

Where reference is made herein to a method comprising two or more defined steps, the defined steps can be carried out in any order or simultaneously (except where the context excludes that possibility), and the method can include one or more other steps which are carried out before any of the defined steps, between two of the defined steps, or after all the defined steps (except where the context excludes that possibility). The term “step of” does not mean “step for”.

The terms “lower,” “upper,” etc. and derived directional terms such as “horizontal”, “vertical”, “upward”, and “downward” are based on a normal configuration of an overlay as shown in the drawings, wherein the overlay fits onto the lower teeth of a patient with their roots extending vertically downward. The term dentist in this text is not be interpreted restrictively and can also be read as dental practitioner, dental technician, dental assistant, dental auxiliary, dental therapist, dental designer, etc.

The present invention provides for a system for use by a dental practitioner (“dentist”) in precisely preparing, revising, or modifying a working tooth for receipt of a preformed restoration such as an inlay, onlay, crown, bridge, or veneer. Such a system has two main components: (i) a dental instrument having features capable of contacting a suitable guiding configuration of an overlay or overlay device and (ii) an overlay or overlay device which can be attached to a working tooth and/or neighboring teeth and configured to limit the three-dimensional movement of a dental instrument, thereby limiting the movement of the dental instrument itself with respect to the tooth being treated. A method of use of the system is further provided in accordance with the present invention.

According to conventional techniques, a diagnostic evaluation of a tooth reveals an existing condition requiring the tooth to be treated by installation of a restoration or prosthesis. Under these conventional approaches, the tooth to be treated is revised and prepared first, and then its revised configuration is used to fabricate the internal configuration of the restoration. Therefore the restoration is fabricated to fit the already prepared tooth.

According to the invention, the system comprising the overlay with a cutting guide and the dental instrument which coordinates with the overlay enables the tooth to be prepared after fabrication of the restoration, where the prepared tooth conforms to the configuration of the existing restoration.

The dentist can prepare a cast or mold of the existing working tooth in the context of neighboring teeth and can identify by x-ray and/or other diagnostic techniques the portions of the working tooth that should be removed, due to e.g., decay, cracks, weaknesses, deterioration, impediment to bite, etc. Based on this information, the invention provides for producing a restoration part, in advance of the physical revision of the tooth so that this restoration part is available to the dentist even before he or she starts physically preparing the tooth. The tooth can then be prepared with precision by using the configured overlay to revise the tooth in a manner to correspond to or mate with the interior of the restoration. The availability of the restoration makes it possible to mount it directly onto the tooth in the same visit that the tooth is prepared. This substantially reduces inconvenience of the patient and reduces the number of visits made to the dentist. This also reduces the possibility of a prepared tooth becoming contaminated during the extended time period between tooth preparation and installation of the final restoration.

Referring now to the drawings, FIG. 1 shows a preferred embodiment of a dental instrument 10 adapted to fit and to coordinate with an overlay device for use in removing portions of tooth structure pursuant to a predetermined configuration, to prepare a working tooth to receive a preformed restoration. In this embodiment, the dental instrument 10 has a hand grip 30 attached to a tooth treatment assembly 50, including for example a dental bur, that is installed within and encapsulated by a projection head 20. As shown in FIG. 1, the tooth treatment assembly and the projection head may be integrated with one another so as to form a monolithic structure described further herein.

As illustrated in FIG. 2, the hand grip 30 provides a portion of the instrument 10 for resting in a human hand and has a shaft that optionally may be hollow along its longitudinal axis. One end of the hand grip 30 is attached to one side of a connecting end 31 which is attached on its other side to the tooth treatment assembly 50. The tooth treatment assembly 50 of FIG. 2 is used when the tooth treatment assembly 50 does not form an integrated, monolithic structure with the projection head 20. The tooth treatment assembly 50 includes a tooth treatment element 52, and appropriate pneumatic and/or mechanical drives well-known in the art that run through the hand grip 30 and may include a housing 40. However, the housing 40 forms part of the projection head 20 in the arrangement in which the tooth treatment assembly 50 and projection head 20 are integrated. In this preferred embodiment, the mechanical drives cause a rotation of a tooth treatment element 52 used for removing tooth structure. It is important to note that the tooth treatment element 52 need not be rotated to accomplish its intended function of removing tooth structure from a working tooth 60, an example of which is shown in FIG. 15. For instance, it may cut through a working tooth in a sawing or milling action. The instrument can also be adapted for a tooth treatment element that removes tooth material by laser or other techniques.

As shown in FIGS. 2-4, the projection head 20 surrounding the tooth treatment assembly 50 preferably has a bottom base 23 from which a side wall 27 extends upwardly and around the periphery thereof leaving an opening 29 on one end. The opening 29 is large enough to accommodate the thickness of the connecting end 31 of the hand grip 30. In the two-piece arrangement of the tooth treatment assembly 50 and the projection head 20, an interior face 28 of the side wall 27 of the projection head 20 preferably wraps around the periphery of the bottom base 23 such that a portion of the side wall 27 approximately conforms to the shape of the housing 40 of the tooth treatment assembly 50. In either arrangement, a tool aperture 24 extends through the thickness of the bottom base 23 and has a shape and size to enable it to accommodate the tooth treatment assembly 50 and to allow water jets or air streams from the tooth treatment 50 assembly to pass through to the working tooth 60. In the preferred embodiment, guide projections 21 extend downwardly from a projection flange 26 that protrudes, often in a horizontal direction away from the bottom base 23 as shown in FIGS. 1 and 3, from the bottom base 23. Alternatively, one or more of these projections 21 could also extend from the bottom base 23 itself. In another alternative arrangement, the projection flange 26 could protrude from a combination of the bottom base 23 as well as the side wall 27.

The guide projections 21 are capable of contacting physical limits, such as those defined by guide surfaces, of a suitable guiding configuration of a predetermined overlay device. In this manner, the suitable guiding configuration can limit the lateral movement of the tooth treatment assembly 50 and corresponding tooth treatment element 52 with respect to the tooth being prepared.

The guiding configuration provides a corresponding limitation on the movement of the entire dental instrument 10 by the user and thus can remove predetermined portions of tooth structure such that when movement of the dental instrument 10 throughout the guiding configuration is complete, the resulting prepared tooth 70, an example of which is shown in FIG. 15, will have dimensions that enable it to be fitted to and mated with the interior of a preformed restoration.

In one embodiment, the projection head 20 is capable of resting on a suitable guiding configuration. Within this configuration, the bottom base 23 of the projection head 20 preferably may have a flat bottom surface 25 as shown in FIG. 3 or a curved surface (not shown), but other arrangements of this surface are within the scope of the present invention. The guide projections 21 extending from the projection head 20 in this configuration preferably have a predetermined length to correspond with the guiding configuration of the overlay device. In this manner, the guide projections 21 will preferably have a length such that each of their ends or extremities 22 do not contact a surface of the suitable guiding configuration when the projection head 20 rests upon a suitable guiding configuration. Because the projection head 20 rests upon the suitable guiding configuration in this arrangement, the guiding configuration limits the movement of the projection head 20 towards the guiding configuration and thus controls the depth of the projection head 20 and thus the tooth treatment assembly 50 and ultimately the depth of penetration of the tooth treatment element 52 into a working tooth 60.

Alternatively, the guide projections 21 may have a predetermined length such that each of their ends 22 does contact a surface of the suitable guiding configuration. In this manner, the guiding configuration limits the movement of the guide projections 21 towards the guiding configuration and accordingly controls the depth of the projection head 20 and ultimately the depth of penetration of the tooth treatment element 52 into a working tooth. In such an arrangement, the projection head 20 may but need not rest upon the guiding configuration.

In some cases, a suitable guiding configuration used in conjunction with the preferred embodiment of the dental instrument 10 may have various spacings amongst its elements. The projection head 20 may be selected with a size and shape that enable it to fit within only preselected or certain of these spacings. For instance, a set of adjacent guide surfaces extending from the base of a suitable guiding configuration may have stepped, or a series of, spacings between guide surfaces, whereby only some of the adjacent guide surfaces will be sufficiently spaced to enable the projection head 20 of the dental instrument to fit.

In another embodiment of the invention, an overlay may be adapted to receive or accommodate a dental instrument, such as the dental instrument 10 previously described herein. FIGS. 5-12 show preferred configurations of such an overlay. In the preferred configurations shown in FIGS. 5-7, an overlay 90 has a predetermined base 80. This base 80 has an open area 81 that extends through the thickness of the base 80 and exposes surfaces of the working tooth 60 or adjacent teeth 65 at least larger than the portions of the tooth structure to be removed. Furthermore, as illustrated in FIG. 7, the base 80 has tooth contacting surfaces 82 that are contoured to provide contact regions capable of contacting one or more teeth to secure the overlay 90 in a suitable position for the predetermined overlay configuration to be used in removing the predetermined portions of tooth structure from the tooth 60 being treated. In this regard, the tooth contacting surfaces 82 may have a shape that substantially corresponds to the outer shape of portions of the working tooth and/or teeth adjacent to the working tooth.

In this arrangement, a first guide wall 86 and a second guide wall 87 which form a first set of guide walls extend vertically from one side of the base 80. As shown in FIGS. 5 and 6, third and fourth guide walls 88, 89 forming a second set of guide walls similarly extend vertically from an opposite side of the base 80. Although not shown in the figures, an overlay may have additional sets of guide walls. Each set of guide walls in the preferred embodiment shown in FIGS. 5 and 6 has first and second guide surfaces 83, 84 on guide walls 86, 87, respectively. However, a set of guide walls may have more or less than two guide walls.

In the preferred embodiment shown in FIGS. 5 and 6, the first and second guide walls 86, 87 are positioned distally along the base 80 whereas the third and fourth guide walls 88, 89 are positioned mesially along the base 80. However, a set of guide walls may be positioned on the buccal or facial and/or lingual or palatal sides of a comparable base 180, as illustrated in FIG. 8. In the preferred embodiment, the first and second guide surfaces 83, 84 of respective guide walls 86, 87 are capable of contacting one or more guide projections of a dental instrument to limit the movement of a tooth treatment element of a dental instrument, such as tooth treatment element 52 of dental instrument 10. Preferably, guide surfaces 83, 84 are spaced apart a sufficient distance to receive such a guide projection.

In the preferred embodiment shown in FIGS. 5 and 6, the guide walls 86, 87 have a substantially uniform thickness in a direction perpendicular to the base 80 lending to a substantially flat surface across the top surface 85 of each of the guide walls 86, 87. Furthermore, guide walls 86, 87 have a substantially equivalent predetermined height above the base 80 which, when coupled with the substantially flat top surface 85, permits a portion of a dental instrument, such as the projection head 20 of the dental instrument 10, to lay across the thickness of adjacent guide walls, often laying flat as in the arrangement shown in FIG. 1. In this manner, the predetermined height of guide walls 86, 87 can limit the movement of a tooth treatment element, such as the tooth treatment element 52 of dental instrument 10, in the direction, which is often the apical direction, of the tooth. In an alternative arrangement, the top surface of a set of guide walls may have a bevel, chamfer, round, indent, or have an alternative shape to allow an overlay to receive a surface of a dental instrument at a variety of angles.

Preferably, during the tooth preparation procedure the overlay 90 should remain fixed and not move once it is placed around the working tooth 60. Moreover, the overlay 90 should remain in a stable position even when a dental instrument intended for use with the overlay 90, such as dental instrument 10, makes contact with it. The position of the overlay 90 can be secured by contact of the contacting surfaces 82 of the overlay 90 with tooth surfaces or by the use of a bonding agent, such as one that is light cured or a temporary cement or by projections from the overlay 90 that engage portions of a tooth, including the working tooth 60, either of the adjacent teeth 65, or dentition on the opposing jaw.

As in the preferred embodiments shown in FIGS. 5 and 6, the guide walls may be curved. In this arrangement, each guide wall within a set of guide walls is substantially curved about the same axis.

In alternative arrangements of preferred embodiments, first and second guide walls of a given set of guide walls may be substantially parallel to one another in a direction parallel to a plane through the longitudinal center lines through the guide walls. For instance, in FIGS. 8 and 9, there are provided first and second guide walls 186, 187 and 286, 287 configured in a manner to limit the movement of a tooth treatment element of a dental instrument in directions substantially parallel to and substantially perpendicular to the proximal surfaces of each working tooth, respectively. In a further alternative arrangement, each guide wall within a given set of guide walls is nonparallel to each other guide wall. In such an arrangement, the spaces between the guide walls of a given set of guide walls may be arranged in a circular pattern as shown in FIG. 10. Although not shown in the figures, the guide walls may also be in a rectangular, triangular, or a number of other configurations.

FIGS. 11-13 illustrate another preferred embodiment for a dental instrument for use in removing a portion of the structure of a working tooth 60 in preparation for a subsequent restoration. The dental instrument includes a hand grip attached to a tooth treatment assembly, often through a connecting end 231. The tooth treatment assembly preferably includes a housing, a tooth treatment element, and appropriate pneumatic and/or mechanical drives as in the tooth treatment assembly 50.

The housing of the tooth treatment assembly is adapted to connect to, and preferably to fit within, a receptacle element portion of an overlay device, such as a receptacle 270 of an overlay 290 described further herein, and is further capable of interlocking with the receptacle. In an alternative arrangement, the housing of the tooth treatment assembly may have certain features for increased stability of the dental instrument. Such features may include a non-circular or asymmetric cross-section or interlocking grooves on the exterior capable of interfacing with an overlay device.

With reference to FIG. 11, the tooth treatment assembly of the dental instrument may be fixed to a receptacle element of the overlay such that it is capable of moving in tandem with the receptacle. In one such arrangement, the tooth treatment assembly may be integrally connected to a receptacle, such as the receptacle 270, such that it is capable of pivoting about a hinge, such as a hinge 242, that connects the receptacle to an overlay device, such as the overlay 290.

Again referring to FIG. 11, when the tooth treatment assembly is attached to a receptacle element connected to an overlay device, the tooth treatment element may protrude through the receptacle element and may extend into an open area of the overlay device, such as the open area 281, such that it is capable of contacting physical limits of a suitable guiding configuration provided by open area 281, of a predetermined overlay device to provide the tooth treatment element 252 with sufficient access to a three-dimensional portion of the tooth to be removed. In this manner, the suitable guiding configuration may act in coordination with the receptacle element to limit the lateral movement of the tooth treatment assembly and corresponding tooth treatment element with respect to the tooth 60 being prepared.

The guiding configuration and receptacle element thus provide a corresponding limitation on the movement of the entire dental instrument by the user and thus the instrument can remove predetermined portions of tooth structure such that when movement of the dental instrument throughout the area through which the receptacle element permits movement within the guiding projection, the resulting prepared tooth 70, an example of which is shown in FIG. 16, will have dimensions that enable it to be fitted to and mated with the interior of a preformed restoration.

In the arrangement shown in FIG. 11 in which the tooth treatment assembly is installed within a receptacle element attached to an overlay, such as the receptacle 270, the overlay may restrain the vertical movement of the receptacle element to limit the movement of the tooth treatment assembly towards the guiding configuration and thus ultimately control the depth of penetration of the tooth treatment element 252 into the working tooth 60.

In another embodiment in accordance with the invention, an overlay 290 may be adapted to receive or accommodate a dental instrument, such as the dental instrument previously described herein. The overlay 290 has a predetermined base 280 that has an open area 281 that extends through the thickness of the base 280 and exposes surfaces of the working tooth 60 or adjacent teeth 65 at least larger than the portions of the tooth structure to be removed as well as a receptacle 270 attached to the base 280. Furthermore, as illustrated in FIG. 13, the base 280 has tooth contacting surfaces 282 that are contoured to provide contact regions capable of contacting one or more teeth to secure the overlay 290 in a suitable position for the predetermined overlay configuration to be used in removing the predetermined portions of tooth structure from the tooth 60 being treated. In this regard, the tooth contacting surfaces 282 may have a shape that substantially corresponds to the outer shape of portions of the working tooth and/or teeth adjacent to the working tooth.

As shown in FIGS. 11 and 12, the receptacle 270 is a feature that is adapted to receive and may congruously surround a portion of a housing of a tooth treatment assembly, such as the housing of the tooth treatment assembly, when the housing is installed within the receptacle 270. The receptacle 270 preferably has a bottom base 223 from which a side wall 227 extends upwardly and around the periphery thereof leaving an opening 229 on one end. The opening 229 is large enough to accommodate the thickness of the connecting end of the hand grip. A combination of the bottom base 223 and the side wall 227 form inner and outer surfaces 273, 274 of the receptacle. The inner surface 273 of the receptacle 270 preferably conforms to the shape of a housing of the tooth treatment assembly, such as the housing of the tooth treatment assembly. The receptacle 270 may further have a head locking feature that is capable of engaging an undercut located on a housing of a tooth treatment assembly, such as the housing of the tooth treatment assembly, and a shaft locking feature that is capable of engaging an undercut located on a connecting end of a tooth treatment assembly, such as the connecting end 231 of the tooth treatment assembly. The outer surface 274 of the receptacle 270 preferably includes a flange 275 extending therefrom. In a preferred arrangement in which the receptacle 270 is circular to conform to a similarly circular tooth treatment assembly, the flange 275 preferably extends circumferentially around the outer surface 274 of the receptacle 270, as in the arrangement shown in FIGS. 11 and 12. A tool aperture 224 extends through the thickness of the bottom base 223 of the receptacle 270 to enable a tooth treatment element as well as water jets or air streams to pass through.

Again referring to FIG. 11, the receptacle 270 may be movably attached to a base surface 284 of the overlay 290. In this manner, the receptacle 270 may be pivotally attached to the overlay 290 through the hinge 242 as shown in FIG. 11. In this manner, the receptacle 270 is capable of rotating about the longitudinal axis of the hinge. Although the hinge 242 is shown as a pin in FIG. 11, any type of a rotational connection between the overlay and the receptacle, such as attaching the receptacle to a roller bearing on the overlay, is within the scope of this invention.

As FIG. 11 further illustrates, when a dental instrument is attached to the overlay 290, a tooth treatment element of the tooth treatment assembly of the instrument may protrude through the tool aperture 224 and may extend into an open area 281 of the overlay 290 such that it is capable of contacting physical limits of a suitable guiding configuration defined by open area 281 of the overlay 290. The receptacle 270 may also include at least one guide projection (not shown) extending towards the open area 281. In this manner the base 280 is capable of coordinating with the hinge 242 and the open area 281 is capable of contacting either or both of the tooth treatment element or the guide projection to confine the movement of the receptacle 270 and thus the tooth treatment assembly to a predetermined three-dimensional region of the working tooth 60.

In an alternative arrangement, a receiving wall 260 is attached to the base surface 284 of the overlay 290. The receiving wall 260 has a rim 265 along its length. In a preferred arrangement, the receiving wall 260 may have notches 261, but alternative arrangements may not have these notches. The receiving wall 260 is preferably placed at a distance away from the hinge 242 such that, during rotation of the receptacle 270, the flange extending from the outer surface 274 of the receptacle 270 is capable of being received within a region between the base surface 284 and the rim 265 of the receiving wall 260. In this manner, the rim 265 may urge the receptacle 270 towards the base surface 284 as the receptacle 270 is rotated about the hinge.

The housing 240 of the tooth treatment assembly 250 is adapted to connect to, and preferably to fit within, a

In another alternative arrangement of this embodiment, as illustrated in FIG. 14, an overlay 390 may have tooth contacting surfaces for contacting portions of tooth structure, an open area 381 that provides access to portions of teeth for removal of tooth structure, a first base section 384, and a second base section 389.

Each of the first base section 384 and the second base section 389 may include a base 383 and an extending portion 391 extending from the base 383. The extending portion 391 of the first and the second base sections 384, 389 may include an outer surface 386 facing in a direction opposite a working tooth 60 and an inner surface 387 facing in a direction towards a working tooth 60 in which the outer and inner surfaces 386, 387 are separated by a thickness 388. Each of the first and the second base sections 384, 389 additionally may include a slot 385 having a length and a width. A further slot 395 wider than the slot 385 is defined adjacent to the slot 385 and between the inner surface 387 of the extending portion 391 and an inner base surface 392 of the base 383, as shown.

As shown in FIG. 14, a receptacle 370 may be attached to each of the first and the second base sections 384, 389 through the use of the slot 385. As in the receptacle 270 disclosed previously herein, the receptacle 370 includes a housing in which a main body of the housing may congruously surround a portion of an assembly housing of a tooth treatment assembly, such as the assembly housing 240 of the tooth treatment assembly 250, when the assembly housing is installed within the receptacle 370. The main body of the receptacle 370 preferably has a bottom base 323 from which a side wall 327 extends upwardly and around the periphery thereof leaving an opening 329 on one end. The opening 329 is large enough to accommodate the thickness of the connecting end of the hand grip. A combination of the bottom base 323 and the side wall 327 form inner and outer surfaces of the main body of the receptacle. The inner surface 373 of the receptacle 370 preferably conforms to the shape of an assembly housing of the tooth treatment assembly, such as the assembly housing 240 of the tooth treatment assembly 250. The receptacle 370 may further have a head locking feature that is capable of engaging an undercut located on an assembly housing of a tooth treatment assembly, such as the assembly housing 240 of the tooth treatment assembly 250, and a shaft locking feature that is capable of engaging an undercut located on a connecting end of a tooth treatment assembly, such as the connecting end of the tooth treatment assembly. A tool aperture 324 extends through the thickness of the bottom base 323 of the receptacle 370 to enable a tooth treatment element, such as the tooth treatment element 252, as well as water jets or air streams to pass through.

The receptacle 370 may additionally include a guide plate 376 attached through a connecting portion of the housing of the receptacle to the bottom base 323. The guide plate 376 has a width. In a preferred arrangement, the width of the guide plate 376 is greater than the width of the slot 385 of the first base surface 384. Further, the connecting portion preferably has a length substantially equal to the thickness of the slot 385 and thus the guide plate 376 is preferably located such a distance from the bottom base 323. In this manner, when the guide plate 376 is inserted through the outer surface 386 and then the thickness of the slot 385 of the first base section 384, the guide plate 376 is held substantially against the inner surface 387 and thus limits the movement of the receptacle 370 in the direction towards the working tooth 60. Further, when the connecting portion attached to the guide plate 376 is inserted within the slot 385, the connecting portion of the receptacle 370 contacts the slot 385 to limit the lateral movement of the receptacle 370 with respect to the working tooth 60 being treated. Such a configuration thus limits the movement of a tooth treatment assembly adapted to fit within the receptacle 370 and a corresponding tooth treatment element with respect to the working tooth 60 being prepared.

In each of the embodiments presented herein, the overlay 290, 390 preferably should remain fixed and not move once it is placed around the working tooth 60. Moreover, the overlay 290, 390 should remain in a stable position even when a dental instrument intended for use with the overlay 290, 390 such as the dental apparatus, makes contact with it. The position of the overlay 290, 390 can be secured by contact of the contacting surfaces 282, 382 of the overlay 290, 390 with tooth surfaces or by the use of a bonding agent, such as one that is light cured or a temporary cement or by projections from the overlay 290 that engage portions of a tooth, including the working tooth 60, either of the adjacent teeth 65, or dentition on the opposing jaw.

It may be possible to utilize the same configuration of an overlay, such as the overlays 90, 290 described previously herein, made for one tooth, in the preparation of a tooth of the same or different patient, where such other tooth has sufficiently similar dimensions, shape and condition. Therefore, it is within the scope of this invention to have some overlays prepared which can be standardized, reused and/or reproduced. Also, it is within the scope of this invention to utilize data obtained in the preparation of prior overlays and restoration parts in the design and generation of new overlays having substantially similar dimensions and shapes.

A dentist may use a dental instrument such as the dental instrument 10 and an overlay configuration such as the overlay 90 previously described to remove portions of the structure of a working tooth with precision. It is generally preferred to retain and utilize as much of a healthy working tooth as practical. When a tooth is damaged or infected, the damaged and/or infected parts of the tooth may have to be removed first, and the tooth may have to be reconstructed before preparing the tooth for further treatment with a restoration device. The preliminary repair or reconstruction of the tooth minimizes the chance that an infection develops underneath a tooth restoration part. This also maximizes the lifetime of the tooth restoration part as the basis for the tooth restoration part, namely the working tooth, no longer contains defective or damaged portions.

Several methods are known for acquiring three-dimensional data from a patient's dentition to determine the portions of a tooth that should be removed based on factors of decay and structural defects, as well as portions of tooth that should be retained intact to provide sufficient strength in the ultimate preparation of a dental overlay configuration. Such data can be retrieved, for example, by processing and analyzing photographs, x-rays or other information taken from the patient's dentition or by directly obtaining such data from the patient through the use of intra-oral scanning devices. Another method is making a physical impression of the dentition and then subsequently scanning this impression or a reversed cast of the impression. Such scanning can be conducted with a CAD/CAM 3D scanning device. Illustrative of such a device is the Activity 101 Scanner from Smart Optics, DentalWings 3-Series Scanner, or 3Shape 710 Scanner of Woburn, Mass., USA. While such a scanning device can scan a model of the dental arch with a tolerance of about 10 μm this does not take into account other error factors obtained from the making of the impression and the casting of the dental impression. In preparing the ultimate restoration part or dental prosthesis, these other error factors or tolerances must be considered.

The CAD program can choose the specific configuration for the overlay, and ultimately the configuration for the prepared tooth by utilizing certain protocols which are based on prior experience for preparing dental prostheses.

After acquiring the three-dimensional data, this data can be processed by a computer so as to determine a portion of tooth structure to be removed from the tooth. The portion of the tooth to be removed will be determined in view of any further tooth treatment required. If a particular shape of the prepared tooth is required for allowing further treatment, the portion for tooth structure removal will be chosen so that after preparation of the tooth, this particular shape will remain.

Determining the portion for tooth structure removal depends on many parameters and will differ from case to case. Parameters include the location of the tooth in the mouth of the patient, amount and location of the damaged tooth structure, distance of the tooth to neighboring teeth, the bite of the patient, etc. In a preferred embodiment, the computer will also take into account the different parts of the tooth such as the enamel, dentin, pulp, cementum, etc. in determining the predetermined part. It is also understood within the general aspects of the invention that the patient's tooth may have to be built up through conventional techniques and materials prior to the actual step of preparation of the tooth, utilizing the overlay or after preparation if the decay is exposed.

According to the invention, the computer is programmed to automatically determine the predetermined part of tooth structure to be removed. However, also according to the invention, the computer can be programmed either by manually selecting parameters or actually inputting code to determine the portion for tooth structure removal subject to additional limitations or parameters imposed by a practitioner. The practitioner's input can be included by visualizing data relating to the tooth onto a computer display and allowing the practitioner to enter a parameter relating to the preparation of the tooth. Preferably, a preview of the tooth is visualized onto the computer display together with a preview of a simulation of the prepared tooth, so as to allow a practitioner to see the impact of chosen parameters onto the prepared tooth. The latter feature provides a larger degree of freedom to the dentist or practitioner to benefit from advice from other practitioners. The method for producing a dentist tool according to the invention enables a less experienced dentist to benefit from computer-assisted recommendations as well as other practitioners.

Next, the dental overlay is installed into the mouth of a patient in a manner to secure the overlay in a position to enable the overlay to limit a dentist's movement of a tooth treatment element of a dental instrument. A dental instrument is then employed into the mouth of a patient by orienting it in a manner such that guide projections extending from the dental instrument are situated between the guide surfaces of two or more guide walls that are arranged in a configuration for contacting the guide projections.

In one embodiment, a bottom surface of a projection head on a dental instrument can rest on a top surface of the guide walls. In this manner, the predetermined height of the guide walls determines the depth of penetration of a tooth treatment element on a dental instrument. When the top surfaces of the guide walls are substantially flat and a portion of a dental instrument such as a projection head is laid across these top surfaces, the dental instrument may be slid along these top surfaces.

Finally, the dentist's instrument may be operated in conjunction with the dental overlay. In this regard, when a tooth treatment element such as a dental bur extends from a dentist's instrument, sliding the dentist's instrument along the top surfaces will produce a predetermined depth or predetermined depths of cut within a prepared tooth 70, as shown in FIG. 10. Accordingly, the limitations of the guide surfaces of the guide walls in conjunction with the limits sets by the height of the guide walls upon a tooth treatment element of a dentist's instrument define a three-dimensional region of the working tooth in which portions of tooth structure are removed.

Although the invention herein has been described with reference to particular embodiments, in both described and illustrated contexts, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. 

The invention claimed is:
 1. A dental system of devices for use in the treatment of a tooth to remove one or more predetermined portions of the tooth, the system comprising: a dental instrument configured for removal of portions of a tooth in the mouth of a patient; an overlay device for temporary installation into the mouth of a patient to receive and to guide the dental instrument in the removal of tooth structure of the tooth to be treated, the overlay device including a base and an extending portion attached to the base, the base of the overlay device having a tooth contacting surface configured for contacting portions of one or more teeth in a patient's mouth to secure the overlay device, without the use of a bonding agent, in a suitable position with respect to the tooth to be treated, and the extending portion of the overlay device defining a slot and being configured for receiving and for use with the dental instrument to limit the movement of the dental instrument during operation, with the overlay device installed over or near the tooth to be treated, to restrict tooth structure removal to the one or more predetermined portions of the tooth to be removed; a housing including a main body and a connecting portion extending from the main body, wherein the housing covers a portion of the dental instrument; and a plate extending from the connecting portion of the housing and being slidable within the extending portion of the overlay device while the main body of the housing is located outside the base and the extending portion of the overlay device, the connecting portion extending through the slot of the extending portion such that the main body and the plate are on opposite sides of the slot, wherein moving the dental instrument moves the plate when the dental instrument is received in the overlay device, and wherein the plate cooperates with the overlay device to limit movement of the dental instrument with respect to the tooth to be treated and to restrict the tooth structure removal to the one or more predetermined portions of the tooth to be removed, the plate being positioned between the base of the overlay device and the extending portion of the overlay device.
 2. The dental system of claim 1, wherein the dental instrument comprises: a hand grip; and a tooth treatment assembly configured for removing at least a portion of the tooth structure of the tooth to be treated.
 3. The dental system of claim 1, wherein the overlay device is configured for preparing the tooth to be treated to receive one or more of a crown, inlay, onlay, bridge, and veneer.
 4. The dental system of claim 1, wherein the base of the overlay device includes an opening configured for receiving a dental bur.
 5. The dental system of claim 1, wherein the tooth contacting surface has a shape that substantially corresponds to an outer shape of the portions of the one or more teeth to be contacted in the patient's mouth.
 6. The dental system of claim 1, wherein the connecting portion is configured to contact the slot to limit the lateral movement of the dental instrument.
 7. The dental system of claim 1, wherein the housing includes an opening configured for receiving a dental bur.
 8. A method for treating a working tooth in a patient's mouth by through the removal of a portions of the working tooth, the method comprising the steps of: mounting a base of an overlay device on either one or both of the working tooth and another tooth, the base including a tooth contacting surface configured for contacting the respective one or both of the working tooth and the other tooth on which the overlay device is mounted to secure the overlay in a suitable position with respect to the working tooth; sliding a plate and housing combination within an extending portion of the mounted overlay device such that a connecting portion of the housing extending between the plate and a main body of the housing slides within a first slot of the extending portion while the main body is located outside the base and the extending portion and such that the plate slides within a second slot of the extending portion located between the first slot and the tooth contacting surface of the base during the sliding of the plate and housing combination, wherein a width of the plate in a first plane is greater than a width of the first slot in a second plane parallel to the first plane, and wherein a portion of the tooth treatment element is received through the plate such that the tooth treatment element extends through the plate; and activating the tooth treatment element for the removal of a portion of the working tooth.
 9. The method of claim 8, further comprising: acquiring three-dimensional data for the working tooth; and processing the three-dimensional data with a computer to define the portion of the working tooth to be removed.
 10. The method of claim 9, wherein the acquired three-dimensional data comprises an exterior shape and size of the working tooth and an interior structure of the working tooth sufficient to detect decay or cracks of the working tooth.
 11. The method of claim 8, wherein the overlay device has one or more open areas exposing the portions of the working tooth to be removed.
 12. The method of claim 8, wherein the overlay device has a configuration that limits the movement of the dental instrument to restrict the portion of the working tooth removed from the working tooth by the dental instrument to a structure configured to be fitted to and mated with an interior of a preformed restoration.
 13. The method of claim 8, wherein the housing includes an opening configured for receiving the tooth treatment element.
 14. The method of claim 8, wherein the tooth contacting surface of the dental overlay device includes tooth contacting surfaces having a contoured shape that substantially corresponds to an outer shape of the respective ones or both of the working tooth and the other tooth.
 15. The method of claim 8, wherein a width of the main body of the housing in a third plane parallel to the second plane is greater than the width of the first slot in the second plane.
 16. A dental assembly for use with a dental instrument in the treatment of a working tooth to remove one or more predetermined portions of the working tooth, the assembly comprising: a dental overlay device configured for receiving the dental instrument and comprising: a base having a tooth contacting surface configured for contacting portions of one or more teeth in a patient's mouth to secure the overlay in a suitable position with respect to the working tooth and one or more open areas exposing the one or more predetermined portions of the working tooth to be removed from the working tooth; and an extending portion extending from the base, the extending portion defining a first slot and a second slot in communication with the first slot and extending between the base and the first slot, the second slot being wider than the first slot; a housing including a main body and a connecting portion extending from the main body; and a round guide plate extending from the connecting portion of the housing and being slideable within the second slot of the extending portion of the dental overlay device while the main body of the housing is located outside the base and the extending portion of the dental overlay device, wherein the extending portion of the dental overlay device is configured to contact the guide plate to limit movement of the guide plate in a direction transverse to a first plane defined by the first slot, wherein the connecting portion extends through the first slot such that the main body and the guide plate are on opposite sides of the first slot, and wherein the guide plate has a width in a second plane parallel to the first plane that is greater than a width of the first slot in the first plane, and wherein the dental overlay device is configured for limiting the movement of the dental instrument in the removal of the one or more predetermined portions of the working tooth when the dental instrument is received in the dental overlay device.
 17. The dental assembly of claim 16, further comprising: a dental instrument attached to the housing and engaged with the guide plate such the dental instrument is slidingly attached to the dental overlay device; and comprising a tooth treatment element for removal of tooth structure.
 18. The dental assembly of claim 17, wherein the housing of the dental overlay device defines a receptacle configured for engagement with the dental instrument such that the dental instrument is interlocked with the receptacle and engaged with the guide plate.
 19. The dental assembly of claim 17, wherein the one or more open areas of the base of the dental overlay device provide sufficient access by the dental instrument to the one or more predetermined portions of the working tooth to be removed from the working tooth.
 20. The dental assembly of claim 17, wherein the extending portion of the dental overlay device is further configured to contact the connecting portion to limit the movement of the dental instrument in a direction parallel to the first plane.
 21. The dental assembly of claim 17, wherein the tooth treatment element is a dental bur.
 22. The dental assembly of claim 16, wherein a portion of the first slot is defined by parallel and facing slot surfaces within planes extending from an outer surface of the extending portion to an inner surface of the extending portion.
 23. The dental assembly of claim 16, wherein the second slot is defined by parallel surfaces.
 24. The dental assembly of claim 16, wherein the first slot is adjacent to the second slot and the connecting portion is slideable in the first slot.
 25. The dental assembly of claim 24, wherein the first slot is configured to limit the lateral movement of the connecting portion.
 26. The dental assembly of claim 16, wherein the extending portion of the dental overlay device comprises a wall attached to the base, the wall partially defining the second slot.
 27. The dental assembly of claim 16, wherein the tooth contacting surface of the dental overlay device includes tooth contacting surfaces having a contoured shape that substantially corresponds to an outer shape of the portions of the one or more teeth in the patient's mouth which the base of the dental overlay device is configured for contacting.
 28. The dental assembly of claim 16, wherein a width of the main body of the housing in a third plane parallel to the first plane is greater than the width of the first slot in the first plane. 